In order to cut off the power in time, existing leakage protective plugs usually includes a tripping mechanism.
FIG. 1 illustrates a utility model application No. 200820099570.0, titled as plug having electricity leakage protection function and previously filed by same applicant as the present invention. Therein, a tripping mechanism comprises a pressing bar 2, and a pressing arm 14 and a big reset spring 11 which are sleeved on the pressing bar 2, wherein the pressing arm 14 is upwardly and downwardly movable in relative to the pressing bar 2, a slot 142 is arranged in the middle of the pressing arm 14, an opening of a tripping plate 9 is positioned in the slot of the pressing arm and may be snapped into a retaining groove 21 of the pressing bar 2 so as to integrate a reset button 1 with the pressing arm 14, wherein an iron core 8 may be moved forwardly by the tripping plate 9 under the spring force of a small spring 5. In the case electric leakage occurs, a high-intensity magnetic field is generated by an electromagnetic coil 6, which enables the tripping plate 9 to be quickly pulled by the iron core 8 and meanwhile the small reset spring 5 may be compressed by the tripping plate 9, so that the tripping plate 9 may get away from the retaining groove 21. Then, the pressing bar 2 is moved upwards quickly under the force of the big reset spring 11, whereby cutting off conducting structure and thus shutting off power.
However, the structure of such leakage protection plug as mentioned in the above patent application is complicated that potential security risks usually exist. For example, during using, the deformation of the tripping plate, which is easily caused by the movement of the iron core during tripping or other external forces, results in technical problems including poor contact of supply circuit and failure of power leakage protecting functions due to un-complete tripping. In addition, such leakage protection plug has a low safety coefficient.